/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_cmplx_dot_prod_f32.c
 * Description:  Floating-point complex dot product
 *
 * $Date:        18. March 2019
 * $Revision:    V1.6.0
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"

/**
  @ingroup groupCmplxMath
 */

/**
  @defgroup cmplx_dot_prod Complex Dot Product

  Computes the dot product of two complex vectors.
  The vectors are multiplied element-by-element and then summed.

  The <code>pSrcA</code> points to the first complex input vector and
  <code>pSrcB</code> points to the second complex input vector.
  <code>numSamples</code> specifies the number of complex samples
  and the data in each array is stored in an interleaved fashion
  (real, imag, real, imag, ...).
  Each array has a total of <code>2*numSamples</code> values.

  The underlying algorithm is used:

  <pre>
  realResult = 0;
  imagResult = 0;
  for (n = 0; n < numSamples; n++) {
      realResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
      imagResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
  }
  </pre>

  There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
  @addtogroup cmplx_dot_prod
  @{
 */

/**
  @brief         Floating-point complex dot product.
  @param[in]     pSrcA       points to the first input vector
  @param[in]     pSrcB       points to the second input vector
  @param[in]     numSamples  number of samples in each vector
  @param[out]    realResult  real part of the result returned here
  @param[out]    imagResult  imaginary part of the result returned here
  @return        none
 */

#if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)

void arm_cmplx_dot_prod_f32(
	const float32_t *pSrcA,
	const float32_t *pSrcB,
	uint32_t numSamples,
	float32_t *realResult,
	float32_t *imagResult)
{
	uint32_t blockSize = numSamples * CMPLX_DIM;  /* loop counters */
	uint32_t blkCnt;
	float32_t real_sum, imag_sum;
	f32x4_t vecSrcA, vecSrcB;
	f32x4_t vec_acc = vdupq_n_f32(0.0f);
	float32_t a0, b0, c0, d0;

	/* Compute 2 complex samples at a time */
	blkCnt = blockSize >> 2U;

	while (blkCnt > 0U) {
		vecSrcA = vld1q(pSrcA);
		vecSrcB = vld1q(pSrcB);

		vec_acc = vcmlaq(vec_acc, vecSrcA, vecSrcB);
		vec_acc = vcmlaq_rot90(vec_acc, vecSrcA, vecSrcB);

		/*
		 * Decrement the blkCnt loop counter
		 * Advance vector source and destination pointers
		 */
		pSrcA += 4;
		pSrcB += 4;
		blkCnt--;
	}


	real_sum = vgetq_lane(vec_acc, 0) + vgetq_lane(vec_acc, 2);
	imag_sum = vgetq_lane(vec_acc, 1) + vgetq_lane(vec_acc, 3);

	/* Tail */
	blkCnt = (blockSize & 3) >> 1;

	while (blkCnt > 0U) {
		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		/* Decrement loop counter */
		blkCnt--;
	}


	/*
	 * Store the real and imaginary results in the destination buffers
	 */
	*realResult = real_sum;
	*imagResult = imag_sum;
}

#else
void arm_cmplx_dot_prod_f32(
	const float32_t *pSrcA,
	const float32_t *pSrcB,
	uint32_t numSamples,
	float32_t *realResult,
	float32_t *imagResult)
{
	uint32_t blkCnt;                               /* Loop counter */
	float32_t real_sum = 0.0f, imag_sum = 0.0f;    /* Temporary result variables */
	float32_t a0, b0, c0, d0;

#if defined(ARM_MATH_NEON) && !defined(ARM_MATH_AUTOVECTORIZE)
	float32x4x2_t vec1, vec2, vec3, vec4;
	float32x4_t accR, accI;
	float32x2_t accum = vdup_n_f32(0);

	accR = vdupq_n_f32(0.0f);
	accI = vdupq_n_f32(0.0f);

	/* Loop unrolling: Compute 8 outputs at a time */
	blkCnt = numSamples >> 3U;

	while (blkCnt > 0U) {
		/* C = (A[0]+jA[1])*(B[0]+jB[1]) + ...  */
		/* Calculate dot product and then store the result in a temporary buffer. */

		vec1 = vld2q_f32(pSrcA);
		vec2 = vld2q_f32(pSrcB);

		/* Increment pointers */
		pSrcA += 8;
		pSrcB += 8;

		/* Re{C} = Re{A}*Re{B} - Im{A}*Im{B} */
		accR = vmlaq_f32(accR, vec1.val[0], vec2.val[0]);
		accR = vmlsq_f32(accR, vec1.val[1], vec2.val[1]);

		/* Im{C} = Re{A}*Im{B} + Im{A}*Re{B} */
		accI = vmlaq_f32(accI, vec1.val[1], vec2.val[0]);
		accI = vmlaq_f32(accI, vec1.val[0], vec2.val[1]);

		vec3 = vld2q_f32(pSrcA);
		vec4 = vld2q_f32(pSrcB);

		/* Increment pointers */
		pSrcA += 8;
		pSrcB += 8;

		/* Re{C} = Re{A}*Re{B} - Im{A}*Im{B} */
		accR = vmlaq_f32(accR, vec3.val[0], vec4.val[0]);
		accR = vmlsq_f32(accR, vec3.val[1], vec4.val[1]);

		/* Im{C} = Re{A}*Im{B} + Im{A}*Re{B} */
		accI = vmlaq_f32(accI, vec3.val[1], vec4.val[0]);
		accI = vmlaq_f32(accI, vec3.val[0], vec4.val[1]);

		/* Decrement the loop counter */
		blkCnt--;
	}

	accum = vpadd_f32(vget_low_f32(accR), vget_high_f32(accR));
	real_sum += vget_lane_f32(accum, 0) + vget_lane_f32(accum, 1);

	accum = vpadd_f32(vget_low_f32(accI), vget_high_f32(accI));
	imag_sum += vget_lane_f32(accum, 0) + vget_lane_f32(accum, 1);

	/* Tail */
	blkCnt = numSamples & 0x7;

#else
#if defined (ARM_MATH_LOOPUNROLL) && !defined(ARM_MATH_AUTOVECTORIZE)

	/* Loop unrolling: Compute 4 outputs at a time */
	blkCnt = numSamples >> 2U;

	while (blkCnt > 0U) {
		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		/* Decrement loop counter */
		blkCnt--;
	}

	/* Loop unrolling: Compute remaining outputs */
	blkCnt = numSamples % 0x4U;

#else

	/* Initialize blkCnt with number of samples */
	blkCnt = numSamples;

#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
#endif /* #if defined(ARM_MATH_NEON) */

	while (blkCnt > 0U) {
		a0 = *pSrcA++;
		b0 = *pSrcA++;
		c0 = *pSrcB++;
		d0 = *pSrcB++;

		real_sum += a0 * c0;
		imag_sum += a0 * d0;
		real_sum -= b0 * d0;
		imag_sum += b0 * c0;

		/* Decrement loop counter */
		blkCnt--;
	}

	/* Store real and imaginary result in destination buffer. */
	*realResult = real_sum;
	*imagResult = imag_sum;
}
#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */

/**
  @} end of cmplx_dot_prod group
 */
